Blue Carbon: Seaweed and Ocean Farming as Climate Solutions

In a previous post, I emphasized the significance of Carbon removal and explored various technology-driven solutions. However, it's essential to acknowledge that technology is not the only approach, and natural solutions, such as reforestation, play a vital role in combating climate change.

This article focuses on one specific natural solution, particularly those involving the ocean. As someone deeply connected to everything related to the ocean, I am passionate about finding ways to preserve its ecosystem. The ocean is not only crucial for its own sake, but it also plays a fundamental role in our planet's health and in the fight against climate change.

This brief summary revolves around the potential of seaweed, kelp, and ocean farming.

My interest in this area peaked in 2021 when I came across an episode on my favorite podcast, Freakonomics radio, featuring Bren Smith, the founder of GreenWave, a non-profit organization dedicated to developing regenerative farming techniques for aquaculture, known as "3D ocean farming." GreenWave's approach aims to create blue carbon, referring to organic carbon captured and stored by marine systems.

Inspired by this discovery, I delved deeper, reading Bren Smith's book, "Eat Like a Fish," and incorporating kelp into my regular diet (yes, every day as part of my breakfast). One of my favorite ways to consume it is through kimchi kelp by Atlantic Sea Farms, much to my wife's amusement.

The role of Blue Carbon

Blue carbon refers to the carbon fluxes and storage that occur in marine systems and can be managed by human intervention. It specifically refers to organic carbon stored in marine or coastal ecosystems, like mangroves, seagrasses, and salt marshes. Despite covering only 1% of the ocean floor, these ecosystems can store up to ten times more carbon per unit area than terrestrial forests!

The ocean already acts as a significant carbon sink, absorbing 90% of the excess heat from anthropogenic greenhouse gas emissions and 30% of anthropogenic CO2 emissions, which mitigates the impact of climate change on land but also damages marine ecosystems, leading to coral reef bleaching, acidification, and disruptions in ocean currents. To address this, ocean-based carbon dioxide removal (CDR) approaches are being explored, leveraging biological and geochemical processes to sequester carbon in various forms in the deep ocean.

This McKinsey report evaluates the potential of blue carbon nature-based solutions (NBS) and assesses their impacts, costs, and potential future funding. It analyzes kelp reforestation and bottom trawling as emerging solutions to reduce costs through economies of scale. The established NBS could potentially offer 0.4 to 1.2 metric gigatons (Gt) of annual CO2 abatement, representing 1 to 3 percent of current annual emissions. With the inclusion of emerging solutions like large-scale seaweed farming and bottom-trawling management, the potential abatement increases to about 3 GtCO2 per year (around 7 percent of current annual emissions). Nascent solutions may add an additional 1 to 2 GtCO2 of annual abatement potential in the longer term, though the science remains uncertain. To provide context, human emissions currently amount to approximately 40 GtCO2 annually.

To learn more about the Carbon Cycle (Slow and Fast Carbon cycle).

The Role of Seaweed Farming

Seaweed farming, particularly kelp cultivation, has emerged as a promising area for carbon removal. Expert panels estimate that kelp has the capacity to remove significant amounts of carbon dioxide each year, making it a potential contributor to combat climate change.

Historically, seaweed holds historical significance in various cultures worldwide. In ancient Japan, prized seaweeds were accepted as tax payments due to their popularity at the imperial court, and seaweed farming has now become a thriving multibillion-dollar industry. The Haenyeo tradition in South Korea involved skilled women collecting seaweeds and mollusks through skin diving, now recognized as a UNESCO Intangible Cultural Heritage. Seaweed provided vital sustenance during Ireland's Great Famine and has been part of the diets in Peru, Chile, and Hawaii for centuries. Across the globe, seaweed's enduring value as a source of nutrients and cultural importance continues to be recognized.

In the 1850s in Cape Cod, Henry David Thoreau described how:

"this kelp, oar-weed, tangle, devil's apron, sole- leather, or ribbon-weed,- as various species are called -appeared to us a singularly marine and fabulous product, a fit invention for Neptune to adorn his car with, or a freak of Proteus. All that is told of the sea has a fabulous sound to an inhabitant of the land, and all its products have a certain fabulous quality, as if they belonged to another planet, from seaweed to a sailor's yarn, or a fish story. In this element, the animal and vegetable kingdoms meet and are strangely mingled."

Seaweed captivated people from diverse backgrounds in the United States, France, and England, sparking interests ranging from scientific study to culinary experimentation and artistic expression. Initially overlooked by botanists, seaweed gained recognition in the mid-1700s, leading to further exploration and classification by marine botanists known as phycologists. Women, excluded from official science academies, found an outlet in seaweed collecting, creating herbaria and albums that combined scientific identification and artistic arrangements. These albums featured dried specimens arranged aesthetically, often shaped into baskets, crosses, or landscapes, and accompanied by poetry and Bible verses. Various types of seaweed books were published, showcasing illustrations through lithography, pressing, and cyanotype photographic methods. Seaweed collecting became a means for coastal communities to engage in both scientific exploration and amateur artistry, revealing their deep interest in the marine environment's materials and aesthetics.

If you are interested in knowing more about the history and uses of seaweed you can’t miss this exhibition in New Bedford (MA).

Ocean Farming as a carbon capture

Governments are finally incentivizing carbon capture, utilization, and storage (CCUS) projects through tax credits. The 45Q tax credit in the US encourages investment in CCUS, particularly for direct air capture (DAC) projects.

While blue carbon solutions offer tremendous potential, there are challenges and uncertainties associated with their implementation. Some of these challenges include limited scientific understanding of certain solutions, such as seaweed farming, and how they impact CO2 levels. Additionally, potential consequences of large-scale interventions in the ocean remain uncertain. Companies must be cautious when buying carbon credits from blue carbon projects, as exaggerated promises could hinder genuine progress on climate change.

While seaweed farming offers a promising method for carbon capture, scientists are still grappling with fundamental questions regarding its feasibility and impact on the environment. Important factors to consider include the scale of seaweed growth, the mechanisms to ensure most of the seaweed sinks to the ocean floor, and the longevity of carbon storage to effectively combat climate.

Running Tide, an aquaculture company based in Maine, is trying to set the standard in the blue carbon market and is conducting field tests in the North Atlantic to determine the optimal conditions for growing various types of kelp. They focus on non-buoyant species of macroalgae and are developing biodegradable floats, aiming to sink the seaweed after it matures. To ensure rigorous evaluation of kelp's carbon removal potential, they collaborate with scientists and establish a scientific advisory team and they have developed in-house algorithms that use sensors and machine vision to monitor and quantify the carbon capture.

The company plans to conduct tests for at least two and a half years to gather comprehensive data on the effects of their practices. Running Tide has ambitious goals and believes that growing and sinking kelp in the deep ocean can be a scalable carbon sequestration solution. They have received significant funding from investors, including tech companies like Shopify and Stripe, who purchase future carbon dioxide removal at high prices to support research and development efforts.

Beyond carbon capture, seaweed presents a range of other valuable applications.

1. Food Ingredients: Seaweed boasts an attractive nutrient profile, containing collagen, amino acids, carbohydrates, fats, protein, vitamins, and essential trace elements like iron. Its popularity as a snack and food ingredient is on the rise. Thank you Atlantic Sea Farms for making my breakfasts so delicious!

2. Animal Feed Additive: Incorporating seaweed into animal feed has the potential to significantly mitigate methane emissions from cattle during enteric digestion. As enteric digestion accounts for 44% of total greenhouse gas emissions from cattle, reducing methane release is critical. Initial research shows that cows belched out 82% less methane after consuming a small amount of red seaweed in their feed for five months. While further study is needed to validate these results at scale, the potential for emission reduction is promising. (look at Ocean Harvest Technology that produces animal feed ingredients based on a variety of proprietary formulas centered on the bioactive ingredients present in different seaweeds).

3. Biopackaging: Seaweed can be utilized as a 100% renewable and biodegradable packaging material. Adopting seaweed-based packaging helps decrease plastic production and its detrimental effects on soil, water, and air. Additionally, it prevents the release of toxic substances that harm marine life and damage natural habitats.

Kelpi, an english startup, has secured more than £3 million fundraising early this year to help it develop its unique compostable packaging from seaweed.

4. Biofertilizer and Biostimulant: Researchers have identified seaweed's potential as a biofertilizer or biostimulant, stimulating organic soil mass growth, improving soil health, and enhancing carbon removal in small amounts.

5. Biofuels: Researchers at USC have been exploring the potential of seaweed as a better biofuel crop compared to mass-produced farm crops like corn. Working with private industry, they have developed a new aquaculture technique using a "kelp elevator" that significantly increases kelp growth on the California coast, yielding four times more biomass than natural processes. This technique could pave the way for open ocean cultivation of kelp crops for low-carbon biofuel, potentially offering a more environmentally friendly alternative to traditional land-based fuel feedstocks like corn and sugarcane.

Marine BioEnergy is developing an open ocean cultivation system for macroalgae biomass to generate biofuel.

There are three main methods for processing wet feedstocks like kelp into fuels: HydroThermal Liquefaction (HTL) followed by Catalytic Hydrothermal Gasification (CHG), Fermentation, and Anaerobic Digestion (AD). HTL/CHG systems convert wet feedstocks into bio-oil, which can be further processed by existing refineries to produce necessary fuels. Fermentation yields alcohols like ethanol or butanol and has been successfully tested with brown kelp sugars. Anaerobic digestion produces methane, which can be injected into pipelines or converted into green methanol or hydrogen for various applications, including fueling generators and powering fuel cells. Several companies and facilities worldwide are actively engaged in these processes, offering renewable and sustainable fuel options.

In Alaska, researchers discovered that Alaska's kelp harvest and fish waste could be converted into a carbon-neutral diesel-like fuel by utilizing existing fish processing plants. This waste-to-energy fuel has the potential to power generators or fishing boats, providing a sustainable and eco-friendly energy source.

In India, Sea6Energy has created the SeaCombine, a unique cultivation mechanism that allows for simultaneous harvesting and replanting of seaweed in deep ocean waters. This innovation enables large-scale production at competitive costs. Additionally, they have developed exclusive technologies to transform fresh seaweed into environmentally friendly products for various sectors such as agriculture, animal health, food ingredients, bioplastics, and renewable chemicals.

Happy to chat and discuss more on this!

Disclaimer: The views and opinions expressed in this article are solely my own and do not reflect the official stance or perspectives of any company or organization. The information presented is based on my personal knowledge, experience, and research. Readers are advised to conduct their own further research and consult relevant sources for a comprehensive understanding of the topics discussed.